• # Conditional Probability

In §4.4 we are introduced to the concept of conditional probability. The notation P(A | B) denotes the probability of event A occurring given that we know event B has occurred.

• What is probability? How is it different from conditional probability?
• What is an everyday example of a question that is based on conditional probability? Create one.
• Now consider the Monty Hall Problem introduced in the following video:

• After watching this video, we know that if we are given the option to switch doors that, probabilistically speaking, it is in our best interest to switch.
• Explain WHY the chance of winning after the host opens a zonk door is NOT 50/50.
• Explain why it is in your best interest to switch doors after a zonk door is opened.
• If the game were based on four doors, and Monty opened two zonks after you had picked your door, what would be the chance of winning? Why?
• # The Normal Probability Distribution

In §6.2 we are introduced to the Normal Probability Distribution and the special case of the Normal Probability Distribution, the Standard Normal Probability Distribution, which is a Normal Probability Distribution with mean (u) zero and variance (σ2) one.

One way to find probabilities from a Standard Normal Distribution is to use probability tables, which are located inside the front cover of your textbook.

• What is a z value?
• What is the purpose of a z value?
• According to the table, what is the probability when z ≤ -1.75? The probability when z ≤ 1.75? How did you find the values?
• What are the values in this table representing?
• What properties of probability distributions and specifically the Normal Probability Distribution do you notice from the two probabilities that you have found in the table?

Do you need an answer to this or any other questions?